data:text/html,<body oninput="document.querySelector('iframe').srcdoc=h.value+'<style>'+c.value+'</style><script>'+j.value+'</script>'"><style>textarea,iframe{float:right;width:100%;height:50%}body{margin:0}textarea{width:33.33%;font-size:18}</style><textarea placeholder=JS id=j></textarea><textarea placeholder=CSS id=c></textarea><textarea placeholder=HTML id=h></textarea><iframe> data:text/html,